Integrating Nature into Cities

Following a long five-month road trip around North America, I’ve decided to move to Los Angeles.

I am just one of millions of people in this country settling down – at least temporarily – within a large metropolitan area, searching for both community and work.

Pacal Mittermaier, global managing director for cities at The Nature Conservancy, noted the incredible rate of urbanization within the United States over the past century (a rate that shows no signs of slowing), writing in the magazine’s most recent edition:

“In 1900, less than 14 percent of all people lived in cities. Today more than half of the world’s population lives in urban settings, and that proportion is projected to increase to more than two-thirds by 2050.”

Los Angeles is a center of liberal thought, progressive ideas, and opportunities to engage in environmental activism. It is an exciting place to begin stepping into a professional field and to challenge myself again intellectually.

Cities, although they take up relatively little of the planet’s surface, can provide a resource-efficient way for people to live. They drive the economy in the United States and function as centers of thought, communication, innovation, art, and learning. Cities harbor some of the richest human diversity in the country and are filled with an amazing array of products, services, and conveniences that provide residents with almost anything they want or need.

However, the decision to move to a city has not been an easy one. I draw inspiration for projects and work from the outdoors. Natural spaces rejuvenate me, providing a sense of peace whenever the industrialized world starts to feel too chaotic. I have my reservations about moving to an area known for its air pollution, congestion, and lack of green space.

And so, my new move comes with a host of questions, including:

How can we make cities and other densely-populated areas happier and healthier places to live?

Can we build cities in ways that are more compatible with the surrounding environment?

What would be the effect of integrating nature into these primarily manmade worlds?

How would access to nature improve the lives of those living in cities?

A recent National Geographic article highlighted various studies demonstrating the positive effect of nature on the human brain. In a recent experiment in Japan, participants who walked through a forest were shown to have significantly lower heart rates, blood pressure readings, and cortisol levels than those participants who walked for an equal length of time through a city center. In Finland, city-dwellers who walked for as little as 20 minutes through an urban park demonstrated fewer physiological signs of stress than those pacing through a concrete-heavy downtown. Another study revealed that children with attention deficit disorders performed better on cognitive tests after walking through parks. A recent experiment led by University of Chicago psychologist Omid Kardan showed that having 11 more trees in a city block, on average, improved residents’ cardio-metabolic health in ways similar to an increase in annual personal income of $20,000, or being 1.4 years younger. In short, it’s becoming increasingly clear that green spaces and trees are great for human health.

Of course, parks, community gardens, and other such green spaces provide additional benefits by providing a safe and calming place for social interaction. Howard Neukru, a leader in the implementation of a natural storm water collection system to keep runoff from polluting the Delaware and Schuylkill Rivers, explains that, “Nature helps a neighborhood rediscover its community.” In large metropolitan areas, urban parks, community gardens, and other natural public areas can help people slow down and connect with one another through picnics, walking dates, musical shows, and other activities and forms of entertainment.

Bringing nature into cities helps better the environment in tangible ways as well, by improving air and water quality. Trees and other vegetation trap and absorb storm water runoff, a major issue in most cities. They also take up carbon dioxide and filter out air pollutants. Pacal Mittermaier in The Nature Conservancy explains, “Smog, soot, and other outdoor pollutants—released by a host of human activities, including the burning wood and fossil fuels, construction, agriculture, and mining—cause an estimated 3.7 million premature deaths every year. Yet numerous studies have shown that trees and other types of vegetation are natural air filters, with the ability to reduce particulate matter concentrations in locations just downwind by 20 to 50 percent.” Los Angeles, a city that (as of 2015) boasted over seven million registered motor vehicles, would greatly benefit from more plants growing along its city streets. As I stand in Malibu and other areas further north of the city, and look back at the cloud of smog shrouding LA, I feel extremely motivated to find ways to make concrete environmental change in the area.

The list of benefits related to trees and green spaces goes on, of course. Plants make a positive difference on the health and safety of the air that we breath, but parks, city gardens, street-side trees filter water as well. Over 3,000 U.S. cities rely on outdated sewer systems that are noncompliant with the Clean Water Act. When these sewers experience storm events that surpass the sewers’ capacities to handle excess water flow, they end up overflowing, and release untreated water into the streets and into local waterways. While Los Angeles receives relatively little precipitation over the course of the average year, being located next to the Pacific Ocean means that water treatment and runoff collection are extremely important to keep wildlife, and the people who fish and use the ocean, safe.

Green rooftops, urban parks, and permeable parking can provide a solution to rain and snow, slowing down and even absorbing significant quantities of fast-moving precipitation before the storm water even reaches the sewers. Vegetation is so effective at trapping, filtering and absorbing water, in fact, that I would support in many areas concentrating public funds into building more green spaces over spending billions of dollars in an effort to enlarge existing sewer systems.

Of course, looking at the longevity of cities as a whole, especially in the face of climate change and sea level rise, it’s important to remember that nature can physically protect cities as well. As we begin to face more and more extreme weather events, it’s important to support the maintenance of natural areas not just within cities, but on the outskirts or borders of urban areas as well.

Swales and marshy ditches built along the perimeter of coastal cities provide homes for native plants. These plants, and varied land contours, help to slow down and filter ocean water coming into the city from the sea, or storm water traveling from the city out into the ocean. Oyster beds and mangroves shelter vulnerable cities from storm swells as well.

Additionally, during heat waves, trees and large bushes keep city temperatures down. In Seoul, South Korea, the restoration of the Cheonggyecheon creek, which runs through the middle of the city, reduced air pollution levels and lowered the average temperature of surrounding city blocks by 5.9 degrees Celsius, providing a welcome relief from the heat for most city dwellers. LA, which UCLA scientists predict will suffer 22 days of extreme heat by 2050 and 54 extreme heat days by 2100, would greatly benefit from trees and additional shade cover in the coming years.

Of course, as we advocate for more natural areas built within cities, we should also be conscious that cities don’t continue destroying wild areas on their outskirts. Urban sprawl caused by poor city planning continues to threaten wilderness areas, and rapid city expansion is currently negatively impacting 10-15% of all vertebrae species.

The surface area of many cities has doubled in the past 30 years, and many urban areas are on pace to double in size again by 2050. Integrating nature into our cities is extremely beneficial to city residents and the internal environment. However, it would be taking one step forward and two steps back if we build city parks and community gardens but continue destroying intact ecosystems on the periphery of these dense living centers.

With foresight and vision, we can build space-efficient cities that incorporate aspects of nature as a way to improve the local environment, enhance both the physical and mental health of residents and better protect infrastructure from natural disasters. We can halt willy-nilly expansion and begin to think innovatively about green city designs that benefit everyone.

How do we make these densely-populated areas happier and healthier places to live in?

We add parks and plant trees, build community gardens, incorporate green roofs, and restore local creeks and rivers.

How do we build cities in ways that are compatible with the surrounding environment?

We build swales to slow storm water runoff into local waterways, support oyster beds, mangroves, and other natural buffers that protect cities from natural disasters, and plant trees and designate parks to improve local air quality.

What would be the effect of integrating nature into these (primarily) manmade worlds?

We would improve the lives of those living there.

I don’t know what life in LA has in store for me, but I’m excited to get involved with local efforts that support the surrounding environment, the ocean-mountain ecosystems, improved air and water quality, sustainable agriculture, better health, and increased happiness among the area’s residents.

I hope that support can be garnered for greener designs and a more beautiful city experience. I hope that there will always be reasons to look forward to the future and that people will continue to work hard and think imaginatively about how we want our lives and spaces to look like in the coming years.

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About Anne

Anne graduated from Duke in May 2015 with a degree in Environmental Science and Policy. She works for an environmental nonprofit helping brands and farmers invest in soil health, regenerative agriculture and climate change reversal. Read More >

Exploring Green

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